Computer Science


DELETE(l)                                               DELETE(l)

NAME
       DELETE - Deletes rows from a table

SYNOPSIS
       DELETE FROM table [ WHERE condition ]

   INPUTS
       table  The name of an existing table.

       condition
              This  is  an  SQL selection query which returns the
              rows which are to be deleted.

              Refer to the SELECT statement for further  descrip-
              tion of the WHERE clause.

   OUTPUTS
       DELETE count
              Message returned if items are successfully deleted.
              The count is the number of rows deleted.

              If count is 0, no rows were deleted.

DESCRIPTION
       DELETE removes rows which satisfy the  WHERE  clause  from
       the specified table.

       If  the  condition (WHERE clause) is absent, the effect is
       to delete all rows in the table.  The result is  a  valid,
       but empty table.

       You must have write access to the table in order to modify
       it, as well as read access to any table whose  values  are
       read in the condition.

USAGE
       Remove all films but musicals:

       DELETE FROM films WHERE kind <> 'Musical';
       SELECT * FROM films;

           code |title                    |did| date_prod|kind      |len
       -----+-------------------------+---+----------+----------+------
       UA501|West Side Story          |105|1961-01-03|Musical   | 02:32
       TC901|The King and I           |109|1956-08-11|Musical   | 02:13
       WD101|Bed Knobs and Broomsticks|111|          |Musical   | 01:57
       (3 rows)

       Clear the table films:

       DELETE FROM films;
       SELECT * FROM films;

           code|title|did|date_prod|kind|len
       ----+-----+---+---------+----+---
       (0 rows)

COMPATIBILITY
   SQL92
       SQL92 allows a positioned DELETE statement:

       DELETE FROM table WHERE
           CURRENT OF cursor

       where  cursor identifies an open cursor.  Interactive cur-
       sors in Postgres are read-only.

SQL - Language Statements 15 August 1999                        1

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